The proposed research entails the behavioral analysis of the role of auditory cortex by ablation-behavior techniques. The ultimate goal is to discover the psychological functions of auditory cortex which enable man to respond appropriately to sounds in his environment. The short-range goals concern the behavioral assessment of the role of auditory cortex in processing species-specific vocalizations. Specifically, the effect of unilaterally ablating auditory cortex in monkeys is to be studied by the application of tests designed to assess some of the psychological capacities involved in hearing and verbal communication. By the experimental study of the basic psychological processes in animals, it is hoped to obtain information relevant to man's psychological processes and, especially, the way in which these capacities fragment as the result of brain damage.